1. Field of the Invention
This invention relations to agricultural implements for treating soil and, more particularly, to an apparatus for supporting agricultural implements and for controlling down pressure on the implements to allow for uniform depth treatment in soils of different consistency.
2. Background Art
It is known to gang mount agricultural implements on a frame so that the implements simultaneously treat underlying soil along laterally spaced rows as the frame is towed. It is also known to apply a variable down pressure on the individual implements. In one form, each implement is carried on one end of an arm that is pivotably connected to a stem, depending from the frame, for movement about a horizontal axis. The opposite end of the arm is acted upon by a spring which biases the arm so that the associated implement is forced downwardly against the underlying soil with a predetermined force.
In one exemplary system, individual coulter wheels are provided on the frame. Each coulter wheel may have an associated fertilizer applicator and/or a trailing tine to open a slot therebehind. Ideally, the fertilizer is applied to the soil at a depth of approximately two inches below the anticipated seed depth. The seed is thereafter planted ideally at a constant depth throughout the field to produce a uniform crop yield and thereby maximize field output.
It is not uncommon for the down pressure on the implements to be set and maintained at one level as the entire field is treated, even though the consistency of the soil may vary throughout the field. To avoid zero production spots throughout the field, the agricultural implements are set to penetrate the hardest soil to be encountered in the field. It is not uncommon for the down pressure on the implements to be set on the order of-300-500 pounds for this purpose.
While the implements urged downwardly with a large force effectively penetrate hardened soil to a desired depth, the implements under this same down pressure penetrate to excessive depths in softer and looser soft.
The user is thus faced with the options of either treating the soil to different depths with a constant down pressure setting or periodically adjusting the down pressure on the implements. This latter option may not be feasible given that numerous adjustments may be required over a given field. Most conventional implements do not lend themselves to simple down pressure adjustment, which makes this task onerous. Even on systems in which the adjustment is facilitated, adjustment is complicated by having to adjust the down pressure on the implements one by one. It is also difficult to set all implements to the same down pressure.
In one such arrangement, a ratchet mechanism is employed. A toothed element cooperates with a translatable rack on the implement stem and is rotatable to set the desired down pressure, with a greater down pressure being used in harder soil and a lesser down pressure being used in softer soil.
Another known system for applying variable down pressure uses a two or four bar linkage which allows the implements to float relative to a fixed frame to which the implements attach. Springs are mounted to the linkage to load the associated implements with a predetermined down pressure. If down pressure is to be adjusted through reorientation of the spring, this must be done for each implement. It is a tedious job to effect this adjustment. Still further, the adjustments become relatively crude and inconsistent from one implement to the next. Also, the links and adjusting mechanisms are prone to detrimental wear, particularly after repeated adjustments are made.
It is also known to reconfigure a frame upon which the implements are mounted to alter the down pressure simultaneously for a group of the implements. In one such prior art device, an intermediate frame assembly is drawn behind the towing vehicle. The intermediate frame has cooperating parts which relatively move in a scissors-like action to selectively raise and lower the implements to vary down pressure. This type of mechanism has a number of drawbacks.
First of all, the structure that allows reconfiguring of the frame is relatively complicated. Increased expense and likelihood of malfunction flow from complex mechanisms, particularly those which are required to withstand the severe environment encountered in the agricultural industry.
Another problem with this scissors-type mechanism is that it is controllable through a wide range of pressures, with there being no way to consistently select and maintain a desired down pressure in hard and soft soils. The user is required to roughly set a desired pressure for different soil conditions. As a result, there may be significant variation in the operating depth for the implements.
Still further, the intermediate frame does not track accurately behind the towing vehicle so that the lines of treatment of upstream and downstream implements may not coincide. It is also known to physically pile weights onto an implement supporting frame to increase down pressure. This is obviously a difficult, time-consuming, and crude manner of adjusting down pressure.